Fluid circuits, such those used in refrigeration and heat pump circuitry, may use a restrictor for controlling the flow through the conduit. The restrictor may be for the purpose of controlling the rate of flow in one direction and permitting unrestricted flow in the other direction.
As the fluid flow about the restrictor under high flow conditions may produce relatively high velocities adjacent the restrictor, and as the restrictor is freely mounted in its associating conduit, it is common for operational noises to be generated. Such noise may be in the form of a rattle, or other vibrations produced by the flow and turbulence of the fluid as it passes around and through the restrictor.
It is an object of the invention to provide a flow control restrictor for use with conduits wherein the operational noise level of the restrictor is substantially reduced as compared with prior art devices.
It is another object of the invention to provide a field-replaceable flow control restrictor for location within conduits wherein the operational noise level is reduced from known restrictor configurations, and wherein the restrictor configuration aids in maintaining the restrictor against its positioning anchor.
In use, a restrictor in accord with the invention is located within a conduit system such as employed in a refrigeration or heat pump circuit and the restrictor will be located intermediate an anchor or abutment and a seat whereby axial movement of the restrictor causes alternative engagement with the anchor or seat depending on the direction of fluid flow. Basically, the restrictor comprises a body of a generally elongated configuration having a first end and a second end located adjacent the anchor and an axial bore intersecting the body ends. A spider portion is defined adjacent to the body second end for radially locating and positioning the restrictor in the conduit, and the first end of the body constitutes a nose region of reduced diametrical dimension as compared to the spider portion. Depending on the direction of fluid movement fluid flow past the restrictor occurs through the spider portion and bore simultaneously or only through the body axial bore.
The flow of fluid is at its maximum when the circuit is in a heat pump heating cycle and as the fluid engages the first end of the body and flows over the nose region vibrations and frequency waves are created tending to produce operational noise or rattling of the restrictor. To reduce such operational noises the restrictor in accord with the invention incorporates a nose region having a cylindrical surface adjacent the restrictor first end which intersects the first end through a transitional spherical segment surface having a center of generation radially aligned with the body axial bore. This spherical segment surface is not tangential to either the nose cylindrical surface, or the nose first end, and the transitional spherical cylindrical surface segment reduces operational noise as compared to prior art restrictors wherein the transitional surface is tangential with the cylindrical nose surface.
Further, the restrictor nose region is provided with an annular radial shoulder adjacent the nose region and cylindrical surface which intersects with a cylindrical flow surface, which, in combination with the radial shoulder, alleviates generated noise. The shoulder radial face or surface is preferably perpendicularly disposed to the restrictor body axis and functions as a piston which aids in axially biasing the restrictor body into engagement with its anchor and reduces rattling and vibration of the restrictor against the anchor. Radial positioning of the restrictor is accomplished by vanes defined on the spider portion wherein the outer ends of the vanes define a periphery having a diametrical dimension only slightly less than the inner diameter of the conduit passage in which the restrictor is located.